Image forming apparatus featuring toner image band formation and adjusting image formation

Abstract

In an image forming apparatus, a control portion forms a restoring toner image (restoring toner band) at a position, in which the refreshing toner image overlaps with a control image with respect to a longitudinal direction of a secondary transfer roller, during post-rotation after image formation in an image forming job is completed. The restoring toner band is formed in a length corresponding to 3 full circumferences of the secondary transfer roller for one-sheet image forming job, 2 full circumferences of the secondary transfer roller for 5-sheet image forming job, and one full circumference of the secondary transfer roller for 10-sheet image forming is job. In the case of an image forming job on 50 sheets or more, a lowering in cleaning performance of a secondary transfer member cleaning device for the secondary transfer roller is not caused to occur, so that the restoring toner band is not formed.

1. An image forming apparatus comprising:
 an image carrying member; 
 toner image forming means for forming a toner image on said image carrying member; 
 a transfer member, pressing a surface of said image carrying member, for forming a transfer portion for electrostatically transferring a toner image onto a recording material, 
 wherein said toner image forming means is capable of forming an adjusting image for adjusting a toner image forming condition on said image carrying member, in a state in which said transfer member contacts said image carrying member, in a period between adjacent image forming operations during continuous image formation; 
 a cleaning member, contactable to said transfer member, for removing toner from said transfer member; and 
 an executing portion capable of executing an operation in a mode, in which a toner band is supplied to said transfer member in a period from completion of image formation in a certain image forming job until start of image formation in a subsequent image forming job, depending on a number of image formations on the recording materials in the certain image forming job, 
 wherein said executing portion executes the operation in the mode when the number of image formations on the recording materials in the certain image forming job is less than a predetermined number. 
 
     
     
       2. An apparatus according to  claim 1 , wherein the toner band has a length longer than a length of the adjusting image with respect to a movement direction of said image carrying member. 
     
     
       3. An apparatus according to  claim 1 , wherein said executing portion increases an amount of toner of the toner band to be supplied to said transfer member with a decreasing number of image formations in an image forming job. 
     
     
       4. An apparatus according to  claim 1 , wherein said executing portion supplies a toner image to said transfer member during a period from the completion of the image formation in an image forming job until rotation of said image carrying member is stopped. 
     
     
       5. An apparatus according to  claim 1 , wherein on said image carrying member, a yellow toner image, a magenta toner image, a cyan toner image and a black toner image are formed, and wherein said executing portion supplies the yellow toner image to said transfer member. 
     
     
       6. An apparatus according to  claim 1 , wherein said image forming apparatus further comprises a detecting portion for detecting the adjusting image and a changing portion for changing a toner image forming condition on the basis of an output of said detecting portion,
 wherein said toner image forming means forms the adjusting image in a state in which said transfer member and said image carrying member contact each other during a period between an image formation and a subsequent image formation. 
 
     
     
       7. An apparatus according to  claim 1 , wherein said cleaning member comprises a brush member, and
 wherein said image forming apparatus further comprises a collecting member for electrostatically collecting toner of the brush member and a removing member for removing the toner from said collecting member. 
 
     
     
       8. An apparatus according to  claim 1 , wherein when the number of image formations performed on the recording materials in the certain image forming job is more than the predetermined number, said executing portion does not execute formation of the toner band to be supplied to said transfer member. 
     
     
       9. An apparatus according to  claim 1 , wherein when the number of image formations performed on the recording materials in the certain image forming job is more than the predetermined number, said executing portion decreases an amount of the toner to be supplied to said transfer member compared with an amount of the toner when the number of image formations performed on the recording materials in the certain image forming job is less than the predetermined number.